From the point of view of the explorer of musical rarities, the most immediately interesting thing about this disc is the opportunity to hear some of the music of Karl Rankl, who does not appear to have troubled the record catalogues before the appearance of three of his songs on a Nimbus disc issued in 2005 and not at all since. Rankl is best known now (if at all) as the founding Music Director of the Royal Opera at Covent Garden in the years following the Second World War. He recruited and trained the orchestra, conducting many London performances in the years that followed; but when Beecham and Kleiber began to make appearances in the pit, he was regarded as outclassed and the General Director David Webster (a man of many passing enthusiasms) effectively dispensed with his services. Just before that date he had been commissioned to write an opera for the 1951 Festival of Britain, for which he had selected the subject of J M Synge’s Deirdre of the Sorrows; following his abrupt departure, any plans for production were unceremoniously shelved, and nobody except Rankl seems to have had any regrets. That was more or less it so far as Rankl’s compositional works were concerned, and this was the first time I have been able to hear any of his music at all; he seems to have been comprehensively ignored not only in his adopted Britain but also in his native Austria, despite his having studied composition with both Schoenberg and Webern. He appears to have done little or nothing to promote his own music during his conducting career, although he wrote eight symphonies; maybe he lacked confidence in his own abilities, since he declined an invitation to edit and complete Schoenberg’s unfinished Jakobsleiter. Nor do I imagine that we would have had the opportunity to hear his sonata, the most substantial of his works ever to appear on a recording, were it not for the fact that it is scored for that rare combination of double-bass and piano.

It is given pride of place on the CD cover (although it is the third-placed item on the disc). Is this a work which would indicate that we should seek out more music from this composer? Well, I am afraid it really doesn’t seem like it. The sonata was written for the well-known bassist Stuart Knussen, but I fear even he would have had his work cut out to breathe life into much of this conscientiously ‘constructed’ music. Rankl seems to have made a deliberate decision to avoid the twelve-tone system of his teachers Schoenberg and Webern, but unfortunately there is insufficient of his own personality to stamp onto the idiom. The final rondo has a degree of vigour and sparkle – with much of the drive stemming from the rhythmic inflections of the piano part – but as a whole this sonata does not suggest that Rankl urgently requires re-evaluation. It may be that his larger-scale works (this sonata was his only work for a solo instrument) have a greater sense of personality and colour than could function in a miniature context.

Given the sheer number of double-bassists in the world, it is odd that more composers have not been enticed to write for the instrument; but apart from some double-bass soloists writing concertos and sonatas for themselves to play, composers seem generally only to have expressed any desire to score for a solo double-bass as a special effect (as in Mahler’s First Symphony) or as the result of a presumably lucrative commission. One of the exceptions, featured here, was Paul Hindemith, who naturally wrote a sonata for double-bass and piano as part of his mission to write sonatas featuring every instrument of the symphony orchestra (including some very rare visitors). But some of these sonatas – and that for double-bass is unfortunately one – seem to be more the result of looking for a challenge rather than any driven compositional inspiration. The first two movements are scherzo-like trifles, and the finale (twice as long as the preceding two put together) is a set of rather predictable variations on a short-breathed theme.

The influence of Hindemith is also clear on the music of Norbert Sprongl, whose two sonatas for double bass constitute more than half of the contents of this disc. Sprongl studied composition under Joseph Marx, but spent most of his life as a schoolteacher only taking up a full-time musical career at nearly the age of 50. And if Karl Rankl is nearly an unknown name nowadays, Sprongl is even more obscure. He seems to have had rather a soft spot for the double bass, writing not only these two sonatas but also a trio for three double basses. His Second Sonata which opens this CD shows not only a sympathy for the instrument but also a greater sense of engagement than we find with Hindemith. The second movement of the sonata, opening with a drone like bagpipes, has a real sense of purpose and onward drive, and at its climax (track 2) seems to expect a real romantic warmth from the instrument in its upper register – a greater warmth, alas, than the double bass seems able to provide here in a recorded balance which is naturalistic to a fault in the extent to which the piano seems to dominate the textures in places. Towards the end of the first movement of the First Sonata there is an unexpected quotation from Shostakovich’s Leningrad Symphony which I presume was intentional, although the booklet note by Toby Deller does not seek to explain it. The slow movement again seems to expect more in the way of passion than it is in the nature of the instrument to provide, but the finale has an infectious bounce which brings the CD to an exciting close.

Leon Bosch and Sung-Suk Kang have an impressive roster of Meridian releases to their credit, and their willingness to explore unfamiliar repertoire deserves every commendation. As I have observed the recorded sound here (at an unidentified venue) seems to favour the piano at the extent of slighting the double bass – a more resonant acoustic might have helped – but both instruments have plenty of presence. The booklet notes are excellent, including a copy of a letter from Rankl to Knussen about the sonata which exposes a surprising (although commendably cautious) uncertainty about the notation of double bass harmonics. For those curious about the music, this disc can be heartily recommended; and the pieces by Norbert Sprongl, which after all make up over half of the contents, are very impressive indeed. The composer is only otherwise represented in the current listings by a duo for mandolin and guitar included in a miscellaneous 1995 recital; Toby Deller refers to some forty orchestral works including four symphonies and five piano concertos that really should repay some investigation.